This disclosure relates to electronic systems and methods to measure, mitigate, and respond to human indicators of unhealthiness in provocative environments. Provocative environments can result from vehicle motion, other stimuli in a person's environment, and/or viewing computer-generated images. The images could be in a virtual reality (VR), an augmented reality (AR), a multi-dimensional (MD), or a synthetic environment.
Motion sickness, spatial disorientation (SD), vertigo, and other motion-induced conditions are a widespread problem. Up to 60% of people have some motion intolerance. Motion sickness affects nearly one third of people who travel by land, sea, or air. Individuals get motion sick and spatially disoriented while riding or driving/piloting cars, trains, buses, planes, boats, or other vehicles. 10 million US patients receive balance (vertigo) therapy costing $1 billion annually. Reasons for treatment are due to disease affecting the vestibular organs, rehabilitation from surgery on the balance organs, recovery from trauma to the head and rehabilitation in patients learning to use prosthetics in the lower extremities.
SD and motion sickness are significant problems in aviation, affecting human performance (cognitive and motor skills) and resulting in the loss of expensive aircraft and human life. Thousands of deaths have been attributed to accidents caused by SD. A recent study showed that 90%-100% of aircrews reported at least one incidence of SD during their flying careers. SD accounted for 11%-14% of USAF mishaps and a mishap fatality rate of 69%, with risk of SD significantly increased in helicopters and fighter/attack aircraft and at night. The most frequent experienced SD episodes are “leans” (92%), loss of horizon due to atmospheric conditions (82%), misleading altitude cues (79%), sloping horizon (75%), and SD arising from distraction (66%). Airsickness has also been identified as a flight training issue. A motion sickness history questionnaire obtained from student pilots in the Air Force revealed an incidence of airsickness of 50%. In a questionnaire to B-1 and B-52 bomber crewmembers, it was reported to be a frequent occurrence among non-pilots in both aircraft, and experienced crewmembers were more likely to report an impact on their duties.
Space motion sickness is experienced by 60%-80% of astronauts during the first two to three days in micro gravity and by a similar proportion during their first few days after return to Earth. Up to 90% of astronauts experienced spatial disorientation during reentry and landing of the shuttle, with prevalence proportional to the length of the mission. Exposure to micro gravity rearranges the relationships among signals from visual, skin, joint, muscle, and vestibular receptors. Congruence between vestibular signals and those from other receptors, as well as between the vestibular otolith and semicircular canal receptors, is disrupted by the absence of gravity. This lack of congruence between sensory exposure to provocative real or apparent motion leads to the progressive cardinal symptoms of terrestrial motion sickness. Space motion sickness may vary slightly with flushing more common than pallor, stomach awareness, malaise, loss of appetite, and sudden vomiting, often without prodromal nausea.
Simulator sickness can be another example of motion sickness. Many military pilots have reported at least one symptom following simulator exposure. In a study of Coast Guard aviators undergoing flight simulator testing, 64% reported adverse symptoms during the first simulator flight and 39% did so during the last flight. 36% of pilots reported motion sickness when training on a Blackhawk flight simulator. More recently, simulator sickness in virtual environments (VE) has become an important issue. VR is already a popular technology for entertainment purposes, and both the U.S. Army and Navy are interested in the training applications of VEs. However, some users of VE experience discomfort during, and/or after, a session in a simulated environment, in equivalent fashion to simulator sickness already noted for flight and driving simulators.
VR sickness (also known as cyber sickness) occurs when exposure to a virtual environment causes symptoms similar to motion sickness symptoms. VR sickness may have undesirable consequences beyond the sickness itself. For example, flight simulator sickness can discourage pilots from using flight simulators, reduce the efficacy of training through distraction, encourage adaptive behaviors unfavorable for performance, and compromise ground safety or flight safety when sick and disoriented pilots leave the simulator. Similar consequences could be expected for VR systems. VR sickness can be a major barrier to using VR, indicating that VR sickness may be a barrier to the effective use of training tools and rehabilitation tools in VR. There are various technical aspects of VR, AR, MD and synthetic environments that can induce visually induced motion sickness (VIMS), such as mismatched motion, field of view, motion parallax, and viewing angle. The amount of time spent in VR, AR, MD and synthetic environments can increase the presence of symptoms. Possible adverse motion-related health effects from VR, AR, MD or synthetic environments can include photosensitive seizures, VIMS, and eyestrain.
Vection has been found to be correlated with levels of VIMS and postural status. The correlation between vection and VIMS has led to the term vection induced motion sickness. Visually induced vection can be quite compelling, and the illusion has been investigated extensively for over a century. Although false perceptions of self-motion are common in a VR, AR, MD or synthetic environment, visual characteristics linked to this type of illusion are not fully understood. Vection can be strongly influenced by various physical aspects. Rotating auditory cues can also induce vection but auditory vection can be much weaker and far less compelling than visual vection, which can be indistinguishable from real motion.
It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary for an understanding of the invention or that render other details difficult to perceive may have been omitted. It should be understood that the invention is not necessarily limited to the particular embodiments illustrated herein.